The last thing the school board wants is media attention. I would inform the superintendant that you WILL be talking to the local news if something isn't done. They don't want to see the Channel 2 problem solvers on their doorstep.
Remember that everyone has a boss. If you aren't getting satisfaction through the school district, there are other avenues.
I think you should get some advice from some crisis hotlines.
Michigan Assault Hotline
1-800-NO-MEANS-NO
Michigan Parent Help Hotline
1-800-942-4357
Rape Abuse Incest National Network
1-800-656-HOPE
School Violence Hotline
1-800-815-TIPS
Listening Ear Crisis Hotline
1-800-231-1127
I believe there is a Michigan anti bullying policy.
See here You can also file sexual harrassment charges.
You can get a police restraining order.
You can contact the Michigan State Police.
Contact your state representative
here. Someone at one of the numbers above should be able to assist you. If you don't get any assistance, contact your local news station. This behavior shouldn't be tolerated. I also suggest that you get your daughter into counceling. She needs to talk with someone.